title: Effect of digital noise reduction on the accuracy of endodontic file length determination.
abstract: OBJECTIVE
  The aim of the present study was to evaluate the measurement accuracy of endodontic file length on periapical digital radiography after application of noise reduction digital enhancement.
  
  
  METHODS
  Thirty-five human single-rooted permanent teeth with canals measuring 20-24 mm in length were selected. ISO #08 endodontic files were placed in the root canals of the teeth. The file lengths were measured with a digital caliper as the standard value. Standard periapical digital images were obtained using the Digora digital radiographic system and a dental X-ray unit. In order to produce the enhanced images, the noise reduction option was applied. Two blinded radiologists measured the file lengths on the original and enhanced images. The measurements were compared by repeated measures ANOVA and the Bonferroni test (α=0.05).
  
  
  RESULTS
  Both the original and enhanced digital images provided significantly longer measurements compared with the standard value (P<0.05). There were no significant differences between the measurement accuracy of the original and enhanced images (P>0.05).
  
  
  CONCLUSIONS
  Noise reduction digital enhancement did not influence the measurement accuracy of the length of the thin endodontic files on the digital periapical radiographs despite the fact that noise reduction could result in the elimination of fine details of the images.
authors.affiliation: Department of Oral and Maxillofacial Radiology, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mojdeh
authors.initials: M
authors.lastname: Mehdizadeh
authors.forename: Abbas Ali
authors.initials: AA
authors.lastname: Khademi
authors.forename: Ali
authors.initials: A
authors.lastname: Shokraneh
authors.forename: Nastaran
authors.initials: N
authors.lastname: Farhadi
keywords: Endodontics; Noise; Radiographic Image Enhancement; Radiography, Dental, Digital